Furnace-door for steam-boilers, &amp;c.



PATENTED DEG. l5, 1.903.l J. T. LINDAHL. FURNAGE DOOR POR STEAM BOILERS,&o.

APPLIATION FILED AUG. 7, 1802.

- 2 SHEETS-SHEET 1.

I0 MODEL.

INR/EMME. TAW

||||||v 1\\\ I HW C l ....||l| l z ---HHHM w. .f5 9 2 1f m .f4 ...A n^\l l/ lll- ,/l\\ n m O4 n f m m I n d.. .....15 ....HTHU 1 n i.. 'In

di Z

'- PATENTE!) DBC. 15, 1903.

J. T. LINDAHL. PURNAGB DOOR FOR STEAM BoILBBs, am.

APPLIUATION FILED UG. 7, 1902.

2 SHEETS-SHEET 2.

H0 MODEL.

VITNEEEEE INVENTOP.

Tu: Noms Pains w. vnnrouwo.. wnsumcmu. n c.

UNITED STATES Patented December 15, 1903.

PATENT OEEICE.

JOHN TEODOR LINDAHL, OF STOCKHOLM, SWEDEN, ASSIGNOR TO CARL ROBERT LAMM,OF STOCKHOLM, SWEDEN.

FU RNACE-DOOR FOR STEAM-BOILERS, 81.0.'

VSPIEIDIIEIGAELION forming part of Letters Patent No. 746,855, datedDecember 1 5, 1903. Application led August 7. 1902. Serial No. 118.724.(No model.)

T0 all whom it may concern.-

Be it known that I, JOHNVTEODORLINDAHL, a subject of the King of Swedenand Norway, and a resident of Stockholm, Sweden, have invented new anduseful Improvements in Furnace-Doors for Steam-Boilers and the Like, ofwhich the following is a specification, reference being had to thedrawings accompanying and forming a part hereof.

This invention relates to improvements in furnace-doors forsteam-boilers and the like.

.As well known, fu rnace-doors for boilers and the like are usually keptopen some minutes each time a new charge of fuel has been brought intothe furnace in order to diminish the generation of smoke due to the saidintroducing of the cold charge of fuel. lf, however, the furnace-door bekept open during a longer time than is necessary-to obviate thegeneration of smoke, the ring will not be economical, and it istherefore desirous to obtain a furnace-door which may automatically letin the air required for obviating the generation of smoke without beingkept open after each introduction of fuel into the furnace.

rlhe object of my presentinvention is,therefore, to provide afurnace-door for boilers and` the like, which by means of a suitableshutter or the like will let in fresh air into-the furnace during acertain predetermined time after the furnace-door has been shut andwhich will preferably simultaneously heat the said air to a certaindegree before it enters the furnace, ak somewhat heated air being, aswell known, much better for the purpose in question than cold air.

The invention consists chiey in providing in the furnace-door a suitableshutter so arranged that it will preferably be automatically opened whenthe furnace-door is opened and be automatically closed a prede--termined time after the furnace-door has been shut and a suitableheating device for the air let in through the opening of the furnacedoornormally closed by the said shutter.

The invention iinally consists in the arrangements and combinations ofparts hereinafter described and claimed.

In the accompanyingr drawings I have shown a suitable constructionalform of my present invention.

Figure l shows a front elevation of my improved furnace-door. Fig. 2 isa plan view ofthe same with the shutter in open position. Fig. 3 shows asection on line A B in Fig. l; Fig. 4., a cross-section on an enlargedscale of a-detail, and Fig. 5 a cross-section on line C D in Fig. et.

Like reference-figures indicate the same parts throughout.

Referring to the drawings, the furnacedoor consists of a frame 1, to theinner side :of which may be fixed a number of lamellse 2, preferablymade of angle-iron, as illustrated in Fig. 2. The said angle-irons 2 maybe held at a suitable distancefrom each other by means of intermediateplates 3 and fixed together by means of screw-bolts el and to jthe saidframe 1 by means of angle-irons 2l preferably containing mercury andadapted to close the said shutter 6. The said apparatus consistsof abody l5, Fig. 4, containing two chambers 8 and 9, connected to eachother by means of achannel 10, in which is arranged a valve 11,tightening when in the position shown in Fig. 4 against a preferablyconical seat 23 in the bottom of the upper chamber 8. The said valve 11may be provided with a small channel (or channels) 13, through which themercury will slowly flow from the chamber 8 into the chamber 9 when theformer stands on a higher level than the latter. To the top of the saidValve ll may be xed a pin 14 or the like of such length that :it willstrike the insideuof the outer end of the chamber 8 or a screw 24,closing the said said valve 11 may for this purpose preferably be oftriangularcross-section, as illustrated in Fig. 5. The outer end of thechamber 9 may also be closed by a screw 25. Between the said chambers 8and 9 and preferably somewhat at the side of the middle of the apparatusis provided a nave 26 or the like by means of which the apparatus isadapted to be fixed to the said axle 7, which preferably runs inball-bearings, so as to be easily-turned. On the pivot 16 of thefurnace-door may be attached a hook 17, the outer part of whichpreferably is bent on a Icircular arc and at the same time forms aninclined guide. The said hook 17 is further so arranged that when thefurnace-door is opened it will engage with the lower part of the saidapparatus 15 and turn the latter from the position shown by full linesin Fig. 3 into the position shown by dotted lines in the same figure, sothat the chamber 9 will come above the chamber 8, the valve 11 therebyleaving its seat 23, so that the mercury in the chamber 9 can rapidlydow into the chamber 8. At the same time the shutter 6, being fixed tothe same axle 7 as the apparatus 15, will be opened and will be kept inopen position by the mercury in the chamber 8 when the fire door isthereupon shut. In order to enable the shutter 6 to be automaticallyclosed by the said apparatus 15, I provide a turnable arm 18 or the likesuitably attached to the one end of the casing 5 and provided at itsouter end with a weight 19', preferably in the form of a roller or thelike. The said weight bears normally against the one of the bearings 20of the said axle 7, but will be lifted by the shutter 6 when the same,while the furnacedoor is being opened, is turned into the said positionshown by dotted lines in Fig. 3. When the furnace-door is thereuponclosed, the hook 17 does not prevent the shutter 6 from being turned, sothe Weight 19 will turn the same into an intermediate position,(represented by the dotted line 27, Fig. 3,) whereby the apparatus 15 isturned so that the chamber 8 will stand somewhat above the chamber 9,and the valve 1l will, on account of its own weight and that of themercury in the chamber 8, fall down onto its seat 23. The mercury willnow gradually fiow back into the chamber 9 through the small channel 13in the said valve 11, whereby the apparatus 15, and thus the shutter 6,will gradually swing back into the position shown by full lines in Fig.3. The speed of said swinging may be predetermined by making thecross-section of the channel 13, respectively, its lower mouth 131 inthe case the latter, as illustrated in Fig. 4, is of smallercross-section than that of the channel 13 itself, to suit.

The arrangements described above may obviously be modified in many wayswithout departing from the principle of the invention. Thus, forinstance, the shutter 6, as well as the heating device for the air, maybe of any convenient form and construction. For the hour-glass-shapedapparatus 15 any other suitable device may be substituted, and vso on.`In order to facilitate the turning of the shutter 6, the axle 7 may bejournaled in wellknown manner in roller-bearings, and the pins of thesaid axle 7 may for the same purpose be arranged eccentrically, though Ihave not illustrated this in the drawings, because the said arrangementsare well understood by any person skilled in the art.A

Having now described my invention and in what manner the same may becarried out, what I claim as new, and desire to secure by LettersPatent, is

1. The combination with a furnace-d oor for boilers and the like of, acasing having an opening, an axle in the said opening, a shutter fixedto the said axle and adapted to close the said opening, anhour-glass-shaped apparatus fixed to the said axle and adapted to Kautomatically close the said shutter a predetermined time after thefurnace-door has been shut, and a number of angle-irons attached to theinside of the door and forming between them passages for the air iowingin through the said casing, substantially as and for the purpose setforth.

2. The combination with a furnace-door for boilers and the like of, acasing having an opening, an axle in the said opening, a shutter fixedto the said axle and adapted to close the said opening, anhour-glass-shaped apparatus fixed to the said axle and adapted toautomatically close the said shutter a predetermined time after thefurnace-door has been shut, a numberof angle-irons attached to theinside of the door and forming between them passages for the air flowingin through the said casing, and a hook adapted to engage the saidhour-glass-shaped apparatus and to turn the same when the furnace-dooris opened, substantially as and for the purpose set forth.

3. The combination with a furnace-door for IOO IIO

boilers and the like of, a casing having an opening, an axle in the saidopening, a shutter fixed to the said axle and adapted to close the saidopening, an hour-glass-shaped apparatus fixed to the said axle andadapted to automatically close the said shutter a predetermined timeafter the furnace-door has been shut, an arm pivotally-fixed to the saidcasing and adapted to turr the said shutter into a certain positionafter the latter has been opened, and a number of angle-irons attachedto the inside of the door and forming between them passages for the airfiowing in through the said casing, substantially as and for the purposeset forth.

4. The combination-with a furnace-door for boilers and the like of, acasing having an opening, an axle in the said opening, a shutter fixedto the said axle and adapted to close the said opening, anhour-glass-shaped apparatus fixed to the said axle and. adapted toautomatically close the said shutter a predetermined time after thefurnace-door has been shut, an arm pivotally xed to the said easing andadapted to turn the said shutter into a certain position after thelatter has been opened, a hook adapted to engage the saidhour-glass-shaped apparatus and to turn the same'when the furnace-dooris opened, and a number of angle-irons attached to the inside of thedoor and forming between them passages for the air flowing in through'the

